A telephone accessory casing for optically signaling the advent of a telephone call can be provided with a plurality of lamp sockets for accommodating respective lamps where illumination is effective through transparent areas of the casing. Arranged within the casing is a print card, i.e. a printed circuit board, which contains the electric switches, circuitry and connections.
Such telephone accessories have been offered under the trade name "VISOTEL" (see U.S. Pat. No. 4,301,335) so as to optically or visually display the reception of an incoming call by a traveling light. Such a device is especially of advantage for individuals with impaired hearing but also in the event the ringing of the telephone cannot be heard because of other noises. Thus such telephone accessories have found widespread interest and have developed into a mass product.
The telephone accessories of this type offered so far have the disadvantage that their housings are not suitable for easy and inexpensive assembly and disassembly and thus do not allow as effective a mass production as one would like. Moreover, their visual and esthetic appearance may not meet customers approval in some cases.